In receiver systems of communication networks, it is necessary to obtain accurate knowledge of phase and frequency of data received, in order to be able to sample and decode the data appropriately. The received data may be aligned to an unknown clock, and many times is subject to noise, jitter, and inter-symbol interference. Mining the data for frequency and phase information is challenging when the data is received at high frequencies and is in a non-return-to-zero (NRZ) format (NRZ data transitions between extreme high (+1) and extreme low (−1) without intermediate zero-level rest phases). Conventional approaches to obtain frequency and phase information of the data incur high power consumption, and are very prone to noise and jitter.
There are long-felt industry needs for techniques to mine data for frequency and phase information which have simple circuits and low power requirements, in order to improve performance of the receiver systems.